A disk of particles orbits a supermassive black hole (modeled after Sgr A*).
Three regions eventually form: A Roche region, where the disk is perpetually well mixed and clumping is minimal, an outer "clumping" region where the disk's self gravity is enough to collect into orbiting bodies, and a third, messy region between the two where clumping often is attempted but never goes anywhere, as the clumps are eventually torn apart by tidal forces and interactions with the rest of the disk.
The simulation of 100,000 particles ran with the IISPH solver at a time-step of 20.28 seconds, and is run for 32 days and 13.5 hours of in-simulation time.